Hd1024 - Teledyne HDO9000 Operator's Manual

HD1024

HD1024 high definition technology offers more quantization levels and greater precision when
digitizing waveforms. HD1024 dynamically reconfigures the ADC based on the number of active
channels and applies bandwidth filters in response to the timebase settings to prevent waveform
aliasing while maintaining high resolution. The HD Mode setting on the
enables/disables HD1024. When HD Mode is Off, the oscilloscope operates in continuous 8-bit
resolution.
HD1024 is enabled by default on all HDO9000 oscilloscopes.
Note: HD Mode does not work with Sequence, Roll, or RIS Sampling Mode acquisitions; these
options are disabled when in HD Mode. Sample Rate is restricted to a minimum 500 ms/s and
the Time/div to a maximum 500 µs. Pre-processor Enhanced Resolution (ERes) and user-
defined linear Interpolation are also disabled; interpolation is handled automatically.
HD1024 Methodology
The HD1024 technology utilizes two principal methods for maintaining high resolution: dynamic ADC
configuration (managing the number of active channels and resolution) and optimized bandwidth
filtering at the input.
Dynamic ADC Configuration
Interleaving allows the oscilloscope to put memory where it is needed to maintain the highest
possible sample rate, and the principal way to do this is to combine digital capabilities into a limited
number of active channels. There are three
Timebase dialog. When in HD Mode, this selection affects the number of bits resolution at which any
channel may operate, as well as sample rate:
Four leaves all channels active for acquisition, optimized for 9-bit resolution.
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Two leaves two channels active for acquisition, C2 and C3, optimized for 10-bit resolution.
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Auto, the default HD1024 selection, dynamically configures the number of active channels and
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the resolution at which they operate depending on which channels are actually active and your
other Vertical and Timebase settings. You can enhance the performance of this selection by
whenever possible attaching your signals to input pairs C1 and C3, C1 and C4, C2 and C3, or C2
and C4. Doing so supports interleaving to 40 GS/s and maintaining 10-bit resolution.
Anti-Aliasing Filters
If the sample rate lowers to a point where waveform aliasing could occur, HD1024 will dynamically
apply bandwidth filters to the input according to the reduction in sample rate in order to ensure that
the Nyquist 2:1 ratio of at least two samples per cycle is met. Lowering bandwidth enables the
instrument to maintain or even raise the total resolution of that channel.
Active Channels options you may select from the
Acquisition
Timebase dialog
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